This invention relates to an improved window covering. More particularly, this invention relates to an improved window covering of the Venetian blind type comprising a plurality of blind slats, wherein one side of the shade is typically arranged to face the interior of a room.
A Venetian blind is widely welcomed as a window covering because it provides the functions of blocking sun rays, adjusting indoor brightness, decorating rooms, providing privacy, etc. A conventional Venetian blind typically includes a head rail, a bottom rail, a plurality of slats, a raising mechanism including multiple raising cords, and a tilting or adjustment mechanism including multiple ladder strings. The lifting member typically comprises cords that are laterally symmetrically provided on the blind to balance the bottom rail and the slats for them to be lowered or lifted synchronously. By pulling the raising cords, the bottom rail and the slats are lifted or lowered relative to the head rail as desired.
The slats can be tilted upward or downward through operation of the tilting mechanism which adjusts the ladder strings. In this regard, each ladder generally includes a front and rear, and vertically-extending members or strings connected to each other by a plurality of vertically-spaced cross-rungs. Supported on each cross-rung, between the vertically-extending members of its ladder, is one length-wise side of a slat. The head rail generally includes this tilting or adjusting mechanism for moving the ladders, so that the vertically-extending members of each ladder move in opposite vertical directions relative to one another, to pivot each slat about its length-wise axis. By tilting the above-mentioned slats to a different angle of inclination, the amount and direction of light projected into a room through the Venetian blind can be controlled and adjusted.
Venetian blinds, however, have the aesthetic drawback that the ladder is partially visible from both the face and back of the blind when closed. This ladder undesirably disrupts the otherwise continuous appearance of the window covering. Also, holes for the raising and tilting cords may also be visible when the Venetian blind is closed. This again detracts from the aesthetic appeal of the window covering, as well as permits additional light to penetrate a room even when the blind slats are closed. The present invention overcomes these shortcomings of the prior art by keeping ladder or other raising and adjustment mechanisms from view when the shade is closed.
An improved Venetian blind type window covering having an open position and a closed position is provided. When in a closed position, the window covering presents a face that conceals a securement member and an adjustment member. The window covering also includes a bottom rail, and a plurality of slats between the head rail and the bottom rail. The securement member and the adjustment member, in cooperation, are suitable for adjustably moving or tilting the plurality of blind slats to open and close the window covering.
The window covering also comprises a head rail having a blind slat tilting mechanism for raising and lowering at least the adjustment member. The blind slat tilting mechanism, in some embodiments, may also raise and lower the securement member. The blind slat tilting mechanism causes positional adjustment of the plurality of blind slats by raising and lowering at least the adjusting member. At least the securement member connects the head rail and a bottom rail with the plurality of blind slats positioned therebetween. Each of the plurality of slats is restrainedly positioned along the securement member at a row interval. The row interval is the distance between adjacent slats as measured along the securement members, and is preferably uniform for the entire window covering. Each of the slats is also restrainedly positioned with the adjustment members. For example, the movement of each plurality of slats relative to the securement members and adjustment members can be restricted by securing the slat to the securement members and adjustment members by way of adhesive, ultra-sonic welding, knitting, tying, or the like. Alternatively, the movement of the slats can be restricted by a ladder assembly extending between the securement member and adjustment member. As yet another alternative, the movement of the slats can be restricted by stop mechanisms positioned on the securement and adjustment members. A rigid securement strip to which the securement and adjustment members are connected can also be utilized to restrict movement of the blind slat relative to the securement and adjustment members. As another alternative, the securement member and the adjustment member may each be a series of cords secured between adjacent slats and thereby operatively connecting the head rail and bottom rail.
The plurality of slats can be formed of a variety of materials, such as wood, aluminum, fabric, or combinations thereof. Each of the plurality of slats further defines a front or distal edge portion which is longer than the row interval such that when the window covering is in the closed position, the securement member and the adjusting member are concealed from the face by the front or distal edge portion of an adjacent slat. For example, the front or distal edge portion can be the longitudinally extending width portion of a slat extending distally from the adjustment member. The portion of the slat extending proximally from the front or distal edge portion is the rear edge portion. When in a closed position, the rear edge portion of the adjacent slat, about which the adjustment member and the securement member are restrainedly positioned, is concealed by the front edge portion of the blind slat as it overlaps a portion of the adjacent slat when the window covering is in a closed position.
A number of cooperating forces are applied to each of the plurality of blind slats. A gravitational closing force is applied about the center of gravity of each of the slats. This gravitational closing force urges the front or distal end portion of the slats to move downwards towards a closed position. A countervailing lifting force is applied to each of the slats by the adjusting member which tends to cause the slats to tilt upwards and to open. A further counterbalancing force is applied to each of the slats by the securement member. This counterbalancing force is preferably greater than the lifting force.
The gravitational closing force is a constant downward force, which is offset by and at equilibrium with the lifting force when the position of the plurality of slats is stationary. When the adjusting member is extended by the tilting mechanism in the head rail, the lifting force is decreased such that the gravitational force overcomes the lifting force and the blind slats are tilted towards a closed position. By contrast, when the adjusting member is retracted by the tilting mechanism in the head rail, the lifting force is greater than the gravitational closing force so the blind slats are tilted upwards or opened.
The counterbalancing force is, however, greater than either of the gravitational force or the lifting force so slats pivot about a longitudinal region proximal to the front or distal edge portion. Where only the adjustment member is raised and lowered, the counterbalancing force is sufficiently great such that the longitudinal region about which the slats pivot is preferably located approximately about the point at which the securement member is restrainedly positioned with the slat and the longitudinal region extending therefrom. This pivot region remains substantially vertically stationary relative to the head rail when the tilting mechanism raises and lowers the adjustment member. Providing a sufficient counterbalancing force can be accomplished in several manners. For example, the bottom rail to which the securement member is connected can be of a sufficiently heavy weight to overcome the lifting force that may be applied to the slats. Alternatively, each slat may include a weighted strip on a proximal end to cause the center of gravity of the slat to shift closer to the longitudinal region such that the force applied to the center of gravity is lessened. As another alternative, each slat can be shaped with a thinner distal end portion to again shift the center of gravity towards the longitudinal region. Different materials may also be used in constructing the slats to achieve the same result. A combination of any of these methods may also be utilized.
As discussed, in some embodiments, the securement member can also be raised and lowered by the tilting mechanism. In particular, the tilting mechanism raises and lowers the securement and adjustment members in opposite vertical directions relative to one another, to pivot each slat about a longitudinal region proximal to the front or distal edge portion.
The securement member can take several forms including cords or a panel of material. An additional benefit of an embodiment of the window covering wherein a panel is utilized is that light may be permitted to enter a room while privacy is maintained. This is an improvement over window coverings, such as standard honeycomb type shades, which are typically made of semi-translucent material that allows light to pass when the shade is closed, while also maintaining a high degree of privacy, but cannot also block light when desired. The present window covering with the panel blocks the majority of light when the slats are closed, and permits light while maintaining privacy with the panel when the slats are open.